Radial seal for rotary regenerative heat exchanger



Jan. 19, 1965 R. w. BELLOWS RADIAL SEAL FOR ROTARY REGENERATIVE HEATEXCHANGER Filed April 13. 1961 Jilin INV EN TOR.

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IIIIIII main 3,166,119 RADIALSEAL FOR ROTARYVREGENERATHVE HEAT EXCHANGER"Richard W. Bellows, Weilsvilie, N.'Y., assignor, by mesne assignments,to Combustion Engineering, Inc, a stock corporation of Delaware FiledApr. 13, 1961, 'Ser. No. 182,725 2 Claims. (Cl. 165-?) Thepresentinvention relates generally to heat exchange apparatus andparticularly to an improved radial sealing V arrangement for use betweenrelatively rotatable parts of a rotary regenerative heat exchanger.

In rotary regenerative heat exchange apparatus of the type hereindefined, a cylindrical rotor has compartments carrying heat transfermaterial which is first exposed to a stream of heating fluid and then,as the rotor is turned about its axis, the compartments of heat transfermaterial are exposed to air or other fluid to be heated passing througha spaced passage where-the heated heat transfermaterial impartsabsorbedheat to the air. The rotor is surrounded by a housing having end orsector plates formed with openings that provide for the flow of heatinggases and air therethrough. To prevent mingling of the two fluids,radial partitions that form the, rotor compartments are provided withradial sealing members adapted to wipe against the imperforate portionsof the sector plate.

Conventionally a rotor for a heat exchanger assumes a dishedconfiguration during operation dueto the differential of expansionbetween the hot end-"that lies adjacent the inlet for the heating fluidand the cold end that lies adjacent the inlet for the cooler fluid to beheated. Since the radial sealing members are usually secured to the endedges 'of the radial partitions insuch a manner that they are forced toconform to the, thermal deformation of the radial partitions to whichthey are attached, the sealing relationship between the sealing membersand the adjacent end plate is easily disturbed to permit extensiveleakage of fluid therebetween.

Thus it maybe seen that sealing means must be readily, adaptable tovarying clearance conditions if .they are to serve their intendedfunction to eifectivelylimit' the leakage of fluids between relativelymovable surfaces. Motivated by this information, radial sealing meanshave else they have been pivoted to the partitions in order that theymight be biased into a sealing arrangement with the confronting surfaceof an adjacent end plate. Such an fecting a practical arrangement fortransforming a thermal change into an actuating force of a magnitudesufficient to move the sealing means towards or away from a cooperatingsealing surface.

. The chief object of this invention therefore is to pro- -vide anarrangement .of sealing means that moves to accommodate a shifting inthe sealing relationship between a rotor and its surrounding housing. 7

A further object of the invention is to utilize as the actuating forcefor an adjustable sealing means the same thermal force that causes theinitial distortion of the rotor.

This invention therefore provides for a specific arrange- 28 in orderthat itmay be rotated slowly about its axis 1 by the motor and reducing'gear arrangement. The'rotor been mounted independent from the radialpartitions or ment that uses an available change of temperature in arotary regenerative heat exchanger to .rna'intain sealing means ingapredetermined sealing relationship a wide range of temperaturevariation.

These and other objects or" my invention more readily apparent when readin conjunction with the drawing in which:

FIGURE 1 is a sectional elevation of a rotary.regenerative heatexchanger involving the inventidnyand FIGURE 2 isan;en1argedsectionalelevation showing the upper and lower radial sealsthatcomprisefthe invention.

ing a cylindrical shell 12 divided into sector shaped compartments byradial partitions14 that .are connected'to a central rotor post16 whichis turned about its axis by means such as, amotor and reduction gearingarrangement shown at 18. The rotor compartments contain a mass of heatabsorbent material, usually in the form of spaced metallic plates, whichfirst absorb heat from the heating fluid entering the heat exchangerthrough a duct 22 that is connected to a boiler or other source of heat.After passing over the heat absorbentmaterial and transmittingheat-thereto, the hot gases aredischarged through an outlet duct 24 towhich an induced draft fan (not illustrated) is usually attached. As therotor turns slowly about its. axis, the heated plates "are moved into astream of air'or other fluid to be heated entering the heat exchangerthrough a duct 26 where their heat to the air. J 1

The rotor is rotatably'mounted on a support bearing is supported forrotation within a cylindrical housing 34 that is provided at oppositeends with end or sector plates 36 which are apertured atcircurnferentially spaced locations 38 and. 40 to admit and dischargethe heating fluid and'the fluid tobe heated. In .order that thefluidtraversing the heat exchanger. do not intermix, the endplates havei'rnperforate portions between apertures 38land 4t) that are at least asgreat in circumferential extent'as one rotor compartment. Radial seals44 which are 'mourited on the end edge of radial partitions 14 areadapted to rub against or in closely spaced relation with the comfronting surface of the adjacent sector plate to eflective ly isolateacomplete 'sectorial compartment between apertures and thus preclude theby-passing of the radial partitions. Other sealing means 46 known ascircumferential seals extend around the end edge of the rotor toprevent.

fluid by-passing the rotorby flowing through the annular clearance space48 between the rotorand housing.

In accordance with the present invention, the radial seals 44 compriseplane metallic leaves that are pivotally secured at their inner endsby-a pivot pin 52 to an end mit movement toward or away from thecon-fronting face of the adjacent end plate in accordance with the relaitive distortion of the rotor andfthe rotor housing' A thermalactuatingbar 54 is positioned substantially parallel to each sealingleaf with its radial inner end secured to the rotor structure at a point56 adjacent the pivot pin 52 in order that its outboard end may be freeto expand or contract radially in' accordance with normal variations intemperature. A bell-crank 58 is pivotally secured to the radialpartition at a-point intermediate the outboard ends of the radial seal44 and the actuating bar 5410 permit linking one arm of the bell crankto the expansion Patented. J at. 19;, 19.6 5 throughout will become 7 Inthe drawings the numeralltl designates a rotor hav the plates give upbar 54 while an angularly displaced arm of the bell crank is linked'tothe adjacent end ot'thesealing means 44.

The exact configuration of the bell crank 58 is not deemed criticalinasmuch as the angular displacement or the relative length" of its armsmay be varied to best comply with existing conditions to provideapredetermined axial movement of the sealing means when the length of theexpansion bar 54 isaltered by a thermal variation. Similarly, anadditional linkage means as illustrated by numeral 60 may be used ateither end of the rotor when necessary to translate a radial movement ofbar 54 to an axial movement of the adjacent seal44.

To provide a suitable actuating force to the sealing 'means,.thethermally responsive actuating bars 54 are necess'arilyformed ofmaterial having a coeflicient 'of'exa pansion different from that of theradial partitions to which they are secured. For the applicationillustrated in the drawing wherein the upper end of the rotor liesadjacent the inlet :for the heating fluid or at the hot end of therotor, the thermal expansion bars must have a coefficient of expansiongreaterthan' that of the :radial partition to which they are attachedin" order that the seals will move upward when the rotor turns downwardin response to a differential of expansion. With a reversal of flowconditions wherein the hot end of the rotorv matter contained in theabove description or shown in the accompanying drawings shall beinterpreted as illustrative only and not in a limiting sense.

I claim: I 1 A I p 1. Regenerative heat exchange'apparatus having arotor that includes a cylindrical'rotor shell joined to a rotor post byradial partitions to form'sectorial compartments that carry a mass ofheat absorbent material, and I a cylindrical housing. surrounding therotor provided at opposite ends thereof -withend plates includingimperforate portions located between circumferentially' spaced aperturesthat direct the flow of heating fluid and" fluid to be heated throughthe heat absorbent material carried by the rotor; radial sealing meansbridging the space between an end edge of each radial partition and theconfronting face of an adjacent end plate adapted to preclude fluid flowtherebetween, said sealing means comprising a leaf member laterallyabutting an endedge 0f the radial partitions and having one endpivotally at- V tached thereto to permit movement of a free end towardand away from the adjacent end plate; a bell crank pi-votally attachedto the radial partition adjacent the free. end of the leaf member;thermal expansion means having one endafiixed to said partition andanopposite end piv- Y otally attached to an arm of said bell crank; anda pivotal linkage between a spacedarmof said bell crank and said freeend of the leaf memberv arranged to transform radial movement of saidthermal expansion means into an axial force moving the sealing leafrelativeto its adjacentend plate.

2 Regenerative heat exchange apparatus having a rotor that includes acylindrical rotor shell joined to a rotor post by radial. partitions toform sectorial compartments that carry a mass of heat absorbentmaterial, and a cylindrical housing surrounding the rotor provided at opposite ends thereof with end plates including imperforate portionslocated between circumferentially spaced apertures that direct the flowof heating fluid and fluid tobe heated through the heat exchangematerial carried by the rotor, radial sealing means bridging the spacebetween an end edge of each r adial partition and the confronting faceof an adjacent end plate to preclude fluid flow therebeto said radialpartition adjacent the rotor post and its outboard end pivotally securedto an arm of the bell crank, and a pivoted linkage connecting a spacedarm of said bell crank and the outboard end of said radial sealing leafwhereby radial movement of said thermal expansion means moves thesealing means axially with respect to its adjacent end plate.

References Cited inthe file of this patent I UNITED sTATEs PATENTS2,650,074 Ballard Aug. 15,1953 2,873,952 -Mudersback A Feb. 17, 19593,088,518 Rayburn May 7, 1963 FOREIGN PATENTS 500,682 Great Britain.Feb. 14, 1939

1. REGENERATIVE HEAT EXCHANGE APPARATUS HAVING A ROTOR THAT INCLUDES A CYLINDRICAL ROTOR SHELL JOINED TO A ROTOR POST BY RADIAL PARTITIONS TO FORM SECTORIAL COMPARTMENTS THAT CARRY A MASS OF HEAT ABSORBENT MATERIAL, AND A CYLINDRICAL HOUSING SURROUNDING THE ROTOR PROVIDED AT OPPOSITE ENDS THEREOF WITH END PLATES INCLUDING IMPERFORATE PORTIONS LOCATED BETWEEN CIRCUMFERENTIALLY SPACED APERTURES THAT DIRECT THE FLOW OF HEATING FLUID AND FLUID TO BE HEATED THROUGH THE HEAT ABSORBENT MATERIAL CARRIED BY THE ROTOR; RADIAL SEALING MEANS BRIDGING THE SPACE BETWEEN AN END EDGE OF EACH RADIAL PARTITION AND THE CONFRONTING FACE OF AN ADJACENT END PLATE ADAPTED TO PRECLUDE FLUID FLOW THEREBETWEEN, SAID SEALING MEANS COMPRISING A LEAF MEMBER LATERALLY ABUTTING AN END EDGE OF THE RADIAL PARTITIONS AND HAVING ONE END PIVOTALLY ATTACHED THERETO TO PERMIT MOVEMENT OF A FREE END TOWARD AND AWAY FROM THE ADJACENT END PLATE; A BELL CRANK PIVOTALLY ATTACHED TO THE RADIAL PARTITION ADJACENT THE FREE END OF THE LEAF MEMBER; THERNAL EXPANSION MEANS HAVING ONE END AFFIXED TO SAID PARTITION AND AN OPPOSITE END PIVOTALLY ATTACHED TO AN ARM OF SAID BELL CRANK; AND A PIVOTAL LINKAGE BETWEEN A SPACED ARM OF SAID BELL CRANK AND SAID FREE END OF THE LEAF MEMBER ARRANGED TO TRANSFORM RADIAL MOVEMENT OF SAID THERMAL EXPANSION MEANS INTO AN AXIAL FORCE MOVING THE SEALING LEAF RELATIVE TO ITS ADJACENT END PLATE. 